This study assesses heavy metal levels in water, soil, and vegetables (swiss chard, lettuce, cabbage, collard green, tomato, green pepper and carrot) irrigated with waste water in Gamo, Ethiopia. The samples of soils, water, and vegetables were randomly collected, processed, and analyzed for heavy metals using atomic absorption spectrophotometry. The results obtained show that the irrigational water is profoundly contaminated with heavy metals Cd, Cr and Ni and Pb, Zn and Cu had the lowest concentration in irrigation water. The levels of Cd in Kulfo river area and Chamo Lake area and Ni in most of the farm soils were also found to be higher than the guideline values. The study also revealed that the mean levels of Cd in most vegetables and Cr and Pb in some vegetables were higher than the maximum recommended limits set by WHO/FAO. In general the results show that the highest concentration of the heavy metals was obtained from Kulfo river area compared to the Arbaminch textile share company area, Abaya Lake area, and Chamo Lake area. Cabbage was maximally contaminated with potential toxic elements followed by Swiss-chard, carrot, tomato, collard green, green pepper and lettuce. Hence, from kulfo river area frequent consumption of cabbage and Swiss chard may cause serious health risks to consumers. The levels of many elements were found to vary with location, suggesting localized inputs of the various contaminants related to industrial and other activities that generate wastewater. This study recommends regular monitoring of heavy metals in soils, waters, and foodstuffs to prevent excessive accrual in food chain.

This study aimed at quantifying the heavy metal levels in soils and vegetables sampled from five suburban regions of Nairobi, Kenya. Using inductively coupled plasma- mass spectrometry (ICP-MS) the metals were quantified from the samples. The assayed heavy metals including Cd, Cr, Co. Cu, Fe, Hg, Mn, Ni, Pb, Zn and the metalloid arsenic were elevated beyond the reference values in both soils and vegetables. High pollutant levels in soils were affiliated to use of industrial and domestic wastewater for irrigation, application of heavy metal containing agrochemicals and geogenic sources of the pollutants. In collard leaves, the uptake of contaminated water via the roots and subsequent accumulation in the leaves was attributable to the observed results. The total hazard quotient (THQ) and hazard index (HI) as a result of arsenic and Hg was >1 in all sampled sites and >10, respectively for both indices and heavy metals. Similarly, the cancer risk (CR) and target cancer risk (TCR) from consumption of collard was greater than the recommended levels of 10-6 and 10-4, respectively with exception of Pb. The indices were indicative of negative non-carcinogenic and carcinogenic effects of consuming the vegetables to the community of the study area. The results of the study, though preliminary, suggest the need to safeguard the health of communities in the study area to ensure that they do not consume heavy metal contaminated vegetables due to the established health effects of such pollutants.

In order to investigate the accumulation and bio-absorption of lead and cadmium in radish and cress, the present study has been conducted in a completely randomized design in three replicates in a hydroponic growing medium. The first factor includes the plant type at two levels (radish and cress), and the second factor is consisted of lead (Pb) (first experiment) at two levels (50 and 100 mg/L), cadmium (Cd) (second experiment) at one level (10 mg/L), and a combination of lead and cadmium (third experiment) again at two levels. After 23 days, roots and aerial parts of both plants have been dried for 48 hours at 70°C in an oven. Then, half gram (0.5 g) of the dried templates has been used to measure the accumulation of Pb and Cd by means of an atomic absorption spectrometer. The highest amount of Pb in radish and crest roots belong to 100 mg/L concentration and the combined Cd (10) + Pb (100) mg/L treatment, respectively, and the highest amount of Cd occurs in Cd (10) + Pb (50) for radish roots and in Cd (10) + Pb (100) combination for cress. Moreover, the Translocation Factor (TF), with a value below 1 and higher bio-concentration factor (BCF) in roots, compared to the aerial part of both radish and cress, seem to be due to the low capability of these plants to transfer Pb and Cd from roots to aerial part. There is a high potentiality for lead accumulation in the roots that prevent its transfer to the aerial part.